"I’ve solved the puzzle," he said. "The fellows have got courage at any rate, and must be as agile as monkeys. There’s a rope hanging down from the last beam,--down the cliff into the water." "A rope!" "Yes, one of our stoutest, cleverly stained so that it’s hardly distinguishable from the rock itself. I caught sight of something swaying, and it took me a few seconds to be sure what it was. Whoever it was that knocked you on the head--Tchigin very likely--he must have climbed the rope, twisted himself up on to the planks, and so got to the mine. It’s a trick I shouldn’t care to attempt." "But how on earth did he get to the rope from the other side? He couldn’t have forded, and the strongest swimmer couldn’t get across with the torrent rushing down at something like eight miles an hour." "That wants thinking out. Meanwhile we’d better get back. If we were seen here we might put somebody on the alert." "Yes. I tell you what: we’ll cross the bridge and stroll up the other side; perhaps we may get a clue there." They walked back without hurry along the planks, spent some little time in their respective sections of the mine, and then, taking their shot guns, crossed the bridge and walked up the narrow road as they had done many times before when shooting. "I’ve been trying to work it out," said Bob as they went. "If I wanted to make for a particular spot on the other side, I should plunge in a good way higher up--you know, where the stream widens and isn’t quite so swift. Then I should strike diagonally across and trust the current to carry me where I wanted to go." "It would sweep you past. You couldn’t be sure of hitting the rope." "I don’t know. We’ll see when we get opposite it." They sauntered on side by side, giving no signs of the carefulness with which they were examining the base of the cliff on the farther side. The bank beneath the road on which they were walking was not precipitous like the opposite cliff. Here and there the rocks shelved down to the water’s edge, but there was no continuous perpendicular barrier. Their course brought them presently opposite the buttress by which hung the rope. They did not pause, but as they strolled on Bob said-- "You see that in the angle formed by that buttress and the cliff there’s a sort of backwater: not exactly a backwater, of course, but the force of the current is much diminished there. If a swimmer got to that point, he could make headway against the stream." "That’s just where the rope hangs. Did you see it?" "No; I only took a passing glimpse. We’ll turn in a few minutes and take a better look going back." They went on. Lawrence shot a ptarmigan which would give colour to the ostensible object of their walk. Then they turned and retraced their steps. As they passed the buttress Bob looked carefully for the rope, and could just discern it by its slight motion against the background of rock. "You might pass a dozen times and never notice it," he said.